1. Field of the Invention
The present invention relates to a power source circuit for providing an output voltage with adjustable temperature characteristics, and a bridge type measuring device with an output compensating circuit utilizing the power source circuit to compensate the temperature characteristics of the bridge type measuring device.
2. Description of the Related Art
A conventional output compensating circuit for a bridge type measuring device is disclosed, for example, in Japanese Unexamined Patent Publication (Kokai) No. 55-155253, which employs adjustable resistors whose resistance values are adjustable to adjust the output gradient and temperature characteristics of the bridge type measuring device.
When the adjustable resistors of the output compensating circuit of the above disclosure are adjusted to compensate the temperature characteristics, a current flowing through the resistor is changed even when the bridge type measuring device is kept at a constant temperature.
This causes a change in the current flowing through an output circuit, thereby causing a change in output voltage.
Namely, the adjustment of the resistors results in shifting the zero point of the output voltage.
To avoid this, the temperature characteristics must be adjusted before the adjustment of the zero point of the output voltage.
Accordingly, there are some restrictions on the adjustment method for each adjustable resistor.